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Carpentry

Chapter 14: APPENDIX III
By Ira Samuel Griffith
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About This Book

A practical manual for apprentices and vocational students that presents step-by-step instruction in building work from site layout and foundations through framing, roof construction, exterior cladding, interior finish, and estimating. It explains foundation setting, sills, joists, wall and partition framing, and detailed procedures for common, hip, valley, and jack rafters, extending methods to octagonal and other polygonal roofs by using trigonometric principles and practical shortcuts. Chapters cover sheathing, roofing, stairs, doors and windows, and include drawings, tables, and an appendix with mathematical tools and estimating guidance.

APPENDIX III

USEFUL TABLES

FRACTIONAL EQUIVALENTS FOR DECIMAL VALUES

.0156 1/64 .2656 17/64 .5156 33/64 .7656 49/64
.0312 1/32 .5312 9/32 .2812 17/32 .7812 25/32
.0468 3/64 .2968 19/64 .5468 35/64 .7968 51/64
.0625 1/64 .3125 5/16 .5625 9/16 .8125 13/16
.0781 5/64 .3281 21/64 .5781 37/64 .8281 53/64
.0937 3/32 .3437 11/32 .5937 19/32 .8437 27/32
.1093 7/64 .3593 23/64 .6093 39/64 .8593 55/64
.125 1/8 .375 3/8 .625 5/8 .875 7/8
.1406 9/64 .3906 25/64 .6406 41/64 .8906 57/64
.1562 5/32 .4062 13/32 .6562 21/32 .9062 29/32
.1718 11/64 .4218 27/64 .6718 43/64 .9218 59/64
.1875 3/16 .4375 7/16 .6875 11/16 .9375 15/16
.2031 13/64 .4531 29/64 .7031 45/64 .9531 61/64
.2187 7/32 .4687 15/32 .7187 23/32 .9687 31/32
.2343 15/64 .4843 31/64 .7343 47/64 .9843 63/64
250 1/4 .500 1/2 .750 3/4 1.000 1

Where rafter lengths are determined by multiplying unit lengths by the run, the answer will almost invariably result in a decimal. Such decimal values may be readily translated into fractional forms by means of the accompanying table.

Example: A roof of ⅓ pitch has a common rafter run of 14'; find the length of common rafter. Answer: 14 × 14.42" = 201.88" or 16.82'. By the table, .82 = 53/64. A carpenter, however, would not care for such accuracy; the nearest 1/16" or even ⅛" would be sufficient.

WOOD AND MACHINE SCREW SIZES

The difference between consecutive sizes is .01316".

No. of
Screw
Gage		 Size of
Number in
Decimals		 No. of
Screw
Gage		 Size of
Number in
Decimals		 No. of
Screw
Gage		 Size of
Number in
Decimals
000 .03152 16 .26840 34 .50528
00 .04486 17 .28156 35 .51844
0 .05784 18 .29472 36 .53160
1 .07100 19 .30788 37 .54476
2 .08416 20 .32104 38 .55792
3 .09732 21 .33420 39 .57108
4 .11048 22 .34736 40 .58424
5 .12364 23 .36052 41 .59740
6 .13680 24 .37368 42 .61056
7 .14996 25 .38864 43 .62372
8 .16312 26 .40000 44 .63688
9 .17628 27 .41316 45 .65004
10 .18944 28 .42632 46 .66320
11 .20260 29 .43948 47 .67636
12 .21576 30 .45264 48 .68952
13 .22892 31 .46580 49 .70268
14 .24208 32 .47896 50 .71584
15 .25524 33 .49212

Frequently the carpenter wishes to know the diameter of hole necessary to receive the shank of a screw of a certain gage. Should a screw gage be accessible, he may readily determine this. Should no gage be at hand, he may determine the size of hole by consulting the accompanying table of Wood and Machine Screw Sizes.

Example: What size bit must be selected to bore a hole for a No. 10 screw. By the table, a No. 10 screw is .18944" in diameter. By the table of Fractional Equivalents for Decimal Values it will be seen that a 3/16" bit must be used. The test for gage of screw is always made over the shank just below the head.

LENGTH AND NUMBER OF WIRE NAILS TO THE POUND

Size LENGTH
INS.		 COMMON CASING FINISH CLINCH FENCE FINE GAL.
SHINGLE
¾ ¾
⅞ ⅞
2d 1 900 1440
3d 1¼ 615 810 568
4d 1½ 322 473 584 250
5d 1¾ 254
6d 2 200 180 300 157 114
7d 2¼ 154
8d 2½ 106 112 190 99 74
9d 2¾ 85
10d 3 74 90 134 69 42
12d 3¼ 57
16d 3½ 46
20d 4 29
30d 4½ 23
40d 5 17
50d 5½ 14
60d 6 11

Nails are sold in quantity by the keg, 100 lbs. of nails, exclusive of the keg. Twenty, 30, 40, 50 and 60d are "base." Other sizes have certain fixed additions per keg to this base price. For example, the price list adopted by manufacturers in 1896 allows an addition per keg of $.70 for 2d common, $.45 for 3d common, etc.

Wire nails are also bought and sold by weight, the size of wire according to the standard wire gage and the length in inches being taken into consideration in specifying the size and in fixing the price per pound.

Common wire nails are thick and have large flat heads. They are used in rough work where strength is desired. Finishing nails are used for fine work such as inside woodwork and cabinet work. Casing nails are somewhat thicker and stronger than finishing nails; they have smaller heads.

WIRE BRADS

Size, inches ½ ½ ⅝ ¾ ¾ ¾ ⅞ ⅞ 1
Wire Gage, nos 20 18 19 19 18 16 18 17 18
Approx no brads to lb. 7500 7200 4267 3556 2758 2600 2364 1781 2069
Size, inches 1 1 1¼ 1¼ 1½ 1½ 1½ 1¾ 1¾
Wire Gage, nos 17 16 17 16 16 15 14 15 14
Approx no brads to lb. 1558 1143 1246 913 761 584 500 500 406
Size, inches 2 2 2½ 2½ 3 3 3
Wire Gage, nos 14 13 13 12 14 12 11
Approx no brads to lb. 350 268 214 164 150 137 105

BOARD MEASURE TABLE

Size
in
INCHES		 Length, in Feet, of Joist, Scantling and Timber
12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
2 × 4 8 9 11 12 13 15 16 17 19 20 21 23 24 25 27
2 × 6 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
2 × 8 16 19 21 24 27 29 32 35 37 40 43 45 48 51 53
2 × 10 20 23 27 30 33 37 40 43 47 50 53 57 60 63 67
2 × 12 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80
2 × 14 28 33 37 42 47 51 56 61 65 70 75 79 84 89 93
3 × 6 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60
3 × 8 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80
3 × 10 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
3 × 12 36 42 48 54 60 66 72 78 84 90 96 102 108 114 120
3 × 14 42 49 56 63 70 77 84 91 98 105 112 119 126 133 140
4 × 4 16 19 21 24 27 29 32 35 37 40 43 45 48 51 53
4 × 6 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80
6 × 6 36 42 48 54 60 66 72 78 84 90 96 102 108 114 120
6 × 8 48 56 64 72 80 88 96 104 112 120 128 136 144 152 160
8 × 8 64 75 85 96 107 117 128 139 149 160 171 181 192 203 213
8 × 10 80 93 107 120 133 147 160 173 187 200 213 227 240 253 267
10 × 10 100 117 133 150 167 183 200 217 233 250 267 283 300 317 333
10 × 12 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400
12 × 12 144 168 192 216 240 264 288 312 336 360 384 408 432 456 480
12 × 14 163 196 224 252 280 308 336 364 392 420 448 476 504 532 560
14 × 14 196 229 261 294 327 359 392 425 457 490 523 555 588 621 653

STRENGTH OF MATERIALS

YELLOW PINE POSTS

Load in Tons

Length
in ft.		 Size in inches
 4 × 4   5 × 5   6 × 6   7 × 7   8 × 8   9 × 9 
8 4 5 6 7 8 9
10 3 4 5 6 7 8
12 2 3 4 5 6 7
14 1 2 3 4 5 6
16 1 2 3 4 5
18 1 2 3 4

HARD PINE BEAMS AND GIRDERS

Load in Tons

Length
in ft.		 Size in inches
 2 × 6   3 × 6   4 × 6   6 × 6   8 × 8 
6 1 1½ 2 3 5½
8 ¾ 1 1½ 2½ 5
10 ¾ 1¼ 2 4½
12 ½ 1 1½ 3
14 ½ 1 2½
16 ½ 2
18 1

STEEL I BEAMS

Load in Tons

Length
in ft.		   Size in inches  
6 8 12
10 7 14 18
12 6 12 16
14 5 10 14
16 4 8 12
18 2 6 10
20 4 8
22 2 6
24 4

BRICK PIERS

Load in Tons

Heigth
in ft.		 Size in inches
 6 × 6   6 × 8   8 × 8   8 × 12   12 × 12   12 × 16   16 × 16 
6 2 3 4 5 6 7 9
8 1½ 2½ 3½ 4¾ 5½ 6 8
10 1 2 3 5 5½ 6 7

STRESSES FOR STRUCTURAL TIMBERS

WORKING UNIT STRESSES USED IN DRY LOCATIONS

Bending Compression
Species of
Timber		 Stress in
extreme
fibre
Lbs. sq.in.		 Horizontal
shear
stress
Lbs. sq.in.		 Parallel to
grain "Short
Columns"
Lbs. sq.in.		 Perpen-
dicular
to grain
Lbs. sq.in.
*Fir, Douglas
    Dense grade 1,600 100 1,200 350
    Sound grade 1,300 85 900 300
Hemlock, eastern 1,000 70 700 300
Hemlock, western 1,300 75 900 300
Oak 1,400 125 900 400
Pine, eastern white 900 80 700 250
Pine, Norway 1,100 85 800 300
*Pine, southern yellow
    Dense grade 1,600 125 1,209 350
    Sound grade 1,300 85 900 300
Spruce 900 70 600 200
Tamarack 1,200 95 900 350

* NOTE: The safe working stresses given in this table are for timbers with defects limited according to the sections on defects in the rules of the Southern Pine Association for Select Structural Material. "Dense" southern yellow pine and "dense" Douglas fir should also conform to the other requirements of this rule. "Sound" southern yellow pine and "sound" Douglas fir require no additional qualifications, whereas the other species should, in addition to being graded for defects, have all pieces of exceptionally low density for the species excluded.

This table gives working unit stresses for structural timbers used in dry locations, and is compiled in the main from material furnished by the Forest Products Laboratory, Madison, Wis.

TABLE OF BRICK WALL CONTENTS IN NUMBER OF BRICKS

Seven Bricks to Each Sq. Ft. of Wall Surface

No. of
sq ft.
of wall		 Thickness
4" 8" 12" 16" 20" 24"
1 7 15 23 30 38 45
2 15 30 45 60 75 90
3 23 45 68 90 113 135
4 30 60 90 120 150 180
5 38 75 113 150 188 225
6 45 90 135 180 225 270
7 53 105 158 210 263 315
8 60 120 180 240 300 360
9 68 135 203 270 338 405
10 75 150 225 300 375 450
20 150 300 450 600 750 900
30 225 450 675 900 1,125 1,350
40 300 600 900 1,200 1,500 1,800
50 375 750 1,125 1,500 1,875 2,250
60 450 900 1,350 1,800 2,250 2,700
70 525 1,050 1,575 2,100 2,625 3,150
80 600 1,200 1,800 2,400 3,000 3,600
90 675 1,350 2,025 2,700 3,375 4,050
100 750 1,500 2,250 3,000 3,750 4,500
Example—Determine the number of bricks in a wall 12" × 18' × 60'.

Solution—The wall contains a surface area of 1,080 sq. ft. By
  the table 100 sq. ft. contains 2,250 bricks, then 1,000 sq. ft. will
  contain 22,500 bricks. 80 sq. ft. will contain, by the table, 1,800
  bricks, making a total of 24,300 bricks.